The present invention is related to a device for influencing the flow in the region of a tube support plate of a tube bundle heat exchanger, for the food and beverage industry in particular, with an outer channel for a heat carrier medium surrounded by an outer shell, with a number of inner tubes which extend axis parallel to the outer shell through the outer channel, forming combinedly an inner channel and being supported in the tube support plate at their respective end sides, with an inlet or outlet common to all the inner tubes, formed in an exchanger flange; and with a common outlet or inlet for a product formed in a connecting piece, and with at least one displacement body influencing the flow in the region of the tube support plate, which is fixedly fastened and which is arranged axially symmetric and concentric to the tube support plate, formed by two portions which form a greatest common exterior diameter at their connecting cross section, with the displacement body, which axially symmetrically divides the flow to or from the inner channel, deflects it towards the outside and by doing so accelerates it in an annular gap cross section which is nozzle-like constricted between the displacement body and an inner contour of the exchanger flange and the connecting piece, respectively, and which subsequently forms an enlarging annular gap cross section together with the inner contour.
A device of this generic kind is known from DE 103 11 529 B3, the entire contents of which is incorporated herein by reference, or from WO 2004/083761 A1, the entire contents of which is incorporated herein by reference. The tube bundle heat exchanger to be considered is described in DE-U-94 03 913, the entire contents of which is incorporated herein by reference. A more recent state of the art relating to this, which is, however, in principle not different from the ancient state of the art, is described in the manufacturer's pamphlet “Röhrenwärmetauscher VARITUBE®” from GEA Tuchenhagen, Liquid Processing Division, 632d-00, of the year 2000, the entire contents of which is incorporated herein by reference.
Because of their cross section geometry, such tube bundle heat exchangers are generally better suited than other constructions of heat exchangers, like plate heat exchangers for instance, for the thermal treatment of products with high and low viscosities, of solid-containing products with whole pieces, pulp or fibres. All the same, even in this it is observed that deposits are formed on the inlet openings of the inner tubes of the tube support plates with fibrous media, like juices with fruit pulp. The treatment at relatively high temperatures favours the agglomeration of fibres and the formation of pulp. These are preferably deposited on the bridges between the multiple parallel arranged inner tubes and on the flat areas of the tube support plate, which are disposed across to the flow direction, and can lead to clogging there. Temporary deposits are released at intervals and the lumps reach the package of the respective product which is designated for the consumer, where they are undesirable and have to be avoided in every case.
The problem described above is resolved in a very satisfying manner by an apparatus proposed in DE 103 11 529 B3, the entire contents of which is incorporated herein by reference, or WO 2004/083761 A1, the entire contents of which is incorporated herein by reference, but only when an active central tube in the centre of the tube support plate can be omitted or is omitted in tube bundle heat exchangers which are to be built new, in order to permit the displacement body to have a fixed, unmovable connection with the tube support plate at this central location. Geometrically optimal tube pitches with 7, 19, 37 and more tubes, which all contain an active central tube, are not possible in this case. Thus, an optimization of the hydraulic design of tube bundle heat exchangers resulting from these so-called tube area pitches must be renounced up to now when the displacement body is to be fixed in the centre of the tube support plate as envisioned in the anterior state of the art.
Furthermore, for back fitting the tube support plate of any tube area pitch what so ever (with or without active central tube) with a displacement body of the kind in discussion here, it is proposed in the anterior state of the art to realise the displacement body as a sphere which is positioned freely movable in front of the tube support plate. Such a sphere is subject to a certain wear, which has to be considered to be hygienically objectionable in sensitive fields of the food and beverage industry.
It is the objective of the present invention to develop further an apparatus of the generic kind, avoiding solutions which are problematic in the hygienic, cleanability and fluid dynamic aspects, such that deposits from solid-containing products in the critical region of the tube support plate are still prevented, without that the latter is subject to limitations in view of desirable tube area pitches, and that simple back fitting of existing tube bundle heat exchangers with a fluidically effective displacement body is possible in addition, without the disadvantages which are hitherto known.